Electrical switch



1931- L. A. M. PHELAN ET AL 1,326,570

ELECTRI CAL SWITCH Original Filed Oct. 22, 1927 fed-"Get. a, 1931 PATENTOFFICE LOUIS A. M. PHELAN, OF CHICAGO, ILLINOIS, AND PAUL 8. BEAR, OFELKHART, INDIANA, ASSIGNOBS, BY MESNE ASSIGNMENTS, TOMINNEAPOLIS-HONEYWELL REGULATOR COMPANY, OF MINNEAPOLIS, MINNESOTA, ACORPORATION OF DELA- WARE ELECTRICAL SWITCH Application filed October22, 1927, Serial No. 228,043. Renewed September 8, 1931.

Our invention relates to electrical switches of the liquid flow type andrefers particularly to mercury contactors that are adapted forcommercial operations and to meet requisite service conditions as tocurrent carrying capacities, voltages, life, reliability, etc.

An object of our present invention is to provide an electrical contactorof the character indicated having an hermetically sealed .0 envelope ofglass or other insulating fragile material, electrodes sealed in theenvelope and a body of mercury therein and being economical tomanufacture and efficient in operation.

Another object of our invention is to provide an electrical contactorhaving an hermetically sealed container of glass or other fragilematerial which houses electrodes, a body of mercury and a filling ofinert gas,

such as hydrogen, the latter being placed within the sealed containerafter the same has been evacuated of air and other deleterious gases.The container is, of course, hermetically sealed at the points wherethe-leading- !5 in wires for the electrodes extend therel0 fective butsuch defects are incapable of bethrough and where the container-istipped ofl" through which the air is exhausted and the hydrogen gas -orother inert gas is filled into the container. Such seals are sometimesdeing discerned by very careful inspection. By our present invention weapply exteriorly of the container, at the points where the seals aremade, a flexible cement which ensures the seals against the developmentof leaks. I

A Another object of our invention is to pro vide a mercury contactorthat is completely covered with the aforesaid flexible cement whichadheres closely to the exterior walls of the container thereby servingas a protective covering or shock-absorbing medium for the fragilecontainer.

Another object of our invention is to provide a mercury contactorwherein the leading-in wires at the points where they project exteriorlyof the envelope and are connected to flexible electrical conductors, thelatter serving to connect the contactor to an external electricalcircuit. are embedded in a body of cement that holds the flexibleconductors in close contact with the envelope thereby preeluding theseconnections from being broken when the flexible conductors are moved,such as occurs constantly when the electrical contactor is being tilted.

Another object of our invention is to provide an electrical contactormounted in a suitable holder which permits the flexible conductorsextending from the contactor to be threaded through the holder therebyminimizing or substantially eliminating all bendvention, reference maybe had to the following description and the accompanying drawings, inwhich Figure 1 is a top plan view, partially in section, of anelectrical contactor embodying one form of our invention;

Fig. 2 is a view, partially in section, and partially in elevation ofthe contactor illustrated in Fig. 1; 4

Fig. 3 is a top plan view of the device of Figures 1 and 2 showing withparticularity a method of embedding the flexible conductors, attached tothe leading-in wires, in the flexible cement that serves both to sealthe envelope and to protect the connections between the flexibleconductors and the leadingin wires from bending movement;

Fig. 4 is a plan view of a modified form of a contactor embodyinganother form of our invention;

Fig. 5 is an end view of the contactor of Fig. 4;

Fig. 6 is a side view, partially in section, of another form of ourinvention;

scope and characteristic features of our inthroughjone "en" Fig. 7 isplan view of the device of Fi 6; I

Fig. 8 is a view in elevation of another cm of a contacto embodying ourinvention; and

Fig. 9 is a view in elevation of another modified'for-m of ourinvention.

Referring toj the device shown in Figs. 1,

2 and'f3-the contactor comprises an envelope 1 made of*fra' ilematerial, such as glass,

I of which leading-in wlres 2- and 3 are sealed by employing a pinchseal construction '4j-of the character utilized in sealingthe'leading-in wires in an incandescent lamp bulbi" The leading-in wires2 and 3 are disposedf 'side by side transversely of the tubularcontainer 1. The leading-in wires may be madeof any suitable materialthat is adapted to'form permanent hermetical seals wlth glass such, forinstance, as the well known Dumet wire. Of course, these leading-inwires may be made of other materials, that serve to produce more or lesssatisfactory seals.' If the fragile container 1 is made of a highmelting glass such as pyrex, the leading-in wires may be made oftungsten. The pinch seal 4 permits the leading-in wires 2 and 3 toextend outwardly beyond the container 1, as shown in the drawings. Theleading-in wires 2 and 3 project interiorly of the container 1 and areprovided at their inner ends with large-headed electrodes 5 and 6. Thecontainer 1 is also evacuated of air and other deleterious gases andpreferably filled with an inert gas, such as hydrogen. The exhaustionand the refilling of thgcontainer 1 is elfected through a tubulationwhich is shown as being sealed off at 7 A body of mercury 8 is housedwithin the container 1 and serves to make and break the elegtrical'circuit between the electrodes 5 an 6.

If the leading-in wires 2 and 3 are made of Dumet or other materialthatis likely to cause deterioration of the contactor in service, theelectrodes 5 and 6 are .then connected to their respective leading-inwires through rods 9 and 10 made of a suitable material, such as iron ortungsten and which rods, in turn, are welded or otherwise secured: atpoints 11 and 12, respectively, to the leadingin wires 2 and 3. Theglass constituting the container 1 is brought down to totally embed theDumet leading-in wires 2 and 3 thereby f precluding their exposureinteriorly of the container.

The materials entering the construction of the contactor described maybe those set forth in U. S. Patent No. 1,598,874, and the method ofattaching the electrodes 5 and 6 to the Dumet leading-in conductors 2and 3 may be that described in U. S. Patent No. 1,598,875. It is to beunderstood, of course, that we are 'not to be limited to the specificmaterials herein described or'thus referred to in the aforesaid patents.The electrodes 5 and 6 may be made of a number of metals, such as .glassknown as Q, 02P an iron nickel, platinum, cobalt, tungsten, mo- 1 bdenumas well as alloys, such as nickelromium alloys or cobalt-iron alloys.The same materials may be employed for making the rods 9 and 10 thatserve to connect the big-headed electrodes 5 and 6 to the leadinginconductors 2 and 3. The container 1 may be made of glass, orcelainpyrex, quartz or d, therefore, when the term glass is used herein, it isto be understood that it comprehends within its meaning such materialsas are enumerated, as well as other materials that are suitable formaking the envelope or container of a mercury contactor.

The pinch seal 4 is of a well known type of construction and has beenemployed in the manufacture of incandescent lamps when the "leading-inwires are sealed into the bulb by a glass sealing machine. Flexibleconductors 13 and 14 are connected respectively to the exteriorlyprojecting portions of the leading-in wires 2 and 3, these flexibleconductors preferably constituting a flexible copper conductor having anexterior braided insulating covering. Flexible conductors of thischaracter are well known in the art. The interior conductin elements ofthe flexible conductors are solfered, welded or otherwise secured, asshown at 15 in Fig. 2, to the leading-in. wires 2 and 3. The flexibleconductors 13 and 14 are then bent so that the portions thereof adjacentto the points of connection to the leading-in wires are in close contactwith the envelope 1. In this manner, the flexible conductors areextended longitudinally of the envelope 1.

The end of the contactor whereat the pinch seal construction 4 obtainsis then completely embedded within a flexible cement 16 which closelyadheres to the walls of the container and serves as a duplicate seal forthe pinch seal construction 4. The cement 16 also impregnates theinsulating covering of the flexlble conductors 13 and 14 and holds theseconductors firmly in contact with the walls of the envelopel. In thismanner the points of connection between the leading-in wires 2 and 3 andthe flexible conductors 13 and 14 are wholly embedded within the cement16 which precludes these points of connection rom being subjected to anymechanical strains or stresses that are likely to interrupt theelectrical circuit comprising the electrodes 5 and 6. N0 bending actioncan be transmitted to these points of connection and. consequently,these connections are retained substantially permanent. The cement 16,besides serving as an extra seal for the pinch seal construction 4 andas a protection for the connections between the flexible conductors 13and 14 and the leading-in wires, constitutes a shock-absorbing mediumfor an blows or shocks that otherwise would brea the fragile or glassenvelope 1. If desired,

terials but is preferably a flexible cellulose for the cement; if ayellow color is desired ester cement or heavy pyroxylin cement, such asa solution of celluloid in acetone or alcohol with the addition of asuitable filler. Coloring material may also be added to the cementthereby imparting any desired color to the tip of the envelope, as wellas to the pinch seal portion 4. If a green color for the ccment 16 isdesired, Paris green or chromium pigment would be suitable coloringagents 7 lead chromate would be a suitable pigment; if a red color isdesired, many of the well known red lake pigments may be employed and ifa white color is desired, zinc oxide lithopone, or chalk maybe employed.Of course, other porcelain cements that adhere to glass and the like mayalso be suitable.

Therefore, the term cement as employed herein comprehends within itsmeaning such materials that are preferably inert and elastic orshock-absorbing when dried, electrically insulating, non-hygroscopic andcapable of providing air-tight seals when applied exteriorly of a glasscontainer.

In Figs. 2 and 3 the contactor is shown as being positioned within aclip holder 17, the same being provided at its rear central portion withan opening 18a by means of which the clip holder 17 may be mechanicallyconnected to any suitablefoperating mechanism. The flexible conductors13 and 14 are threadted through the clip holder 17 as shown in Fig. 3.The axis of the tilting movementof the contactor coincides with the axisof the opening 18 formed in the clip holder and,

therefore, when the flexible conductors l3 and 14 are threaded throughthe holder 17 the mechanical resistancethat these conductors may offerto the tilting movement of the contactor is substantially minimized. Atthe same time, this constructionprecludes the conductors 13 and 1 4 frombeing subjected to bending movements adjacent to the cement covering 16and the pinch seal 4.

In the specific construction illustrated in Figs. 1 to 5, inclusive, anelectrical contactor is shown having atubular glass container whereinthe diameter of the envelope 1 is minimized by reason of my presentinvention. The electrodes Sand 6 of thecontactor of Figs; 1 to 3,inclusive, possess large heads. are of substantial concentrated mass andare disposed at the same end of the container which embodies the pinchtype of seal. As hereinbefore stated, the pinch type of seal is highlyadvantageous for the reason that contactors embodying this form of sealmay be machine made. In this form of contactor the while, at the sametime, the diameter of the' container 1 is minimized by reason of thestaggered positioning of the electrodes 5 and 6 therein. At the sametime, a pinch seal may be employed permitting of the contactor to bemachine made. The quantity of mercury 8 required in a contactor of thisconstruction is considerably reduced over that which would be requiredin a contactor wherein big-headed electrodes are placed side-by-side andspaced from each other transversely of the container.

In Figs. 2 and 3, the flexible electrical conductors 13 and 14 are shownas being brought through the body of cement 16 at the top of theenvelope 1. In the contactor illustrated in Figs. 5 and 6, theleading-in conductors 13' and 14 are shown embedded in the cement 16 insuch manner that they extend longitudinally of the envelope 1 along oneof its sides, in this instance, on the side of the container adjacentthe rear portion of the clip hoider 17. The positioning of the contactorof Fig. 4 within the clip holder 17 is best illustrated in Fig. 5wherein the flexible conductors 13' and 14 are shown as being superposedupon each other at the end of the envelope but extending longitudinallythereof on that side of the envelope which permits of the flexibleconductors 13 and 14' being threaded through the clip holder 17 asshown.

In'the contactor of Figs. 6 and 7, the pinch sealconstruction is usedbut the electrodes 18 and 19 are shown asconstituting, extensions to theleading-in wires and as being placed side-by-side and spaced from eachother transversely of the container. The electrodes 18 and 19 are not ofthe big-headed type of construction, such as the electrodes 5 and 6 ofthe contactor hereinbefore described. If the leading-in wires to'whichthe electrodes 18 and 19 are attached are made of tungsten or some othermetal which does not cause deterioration of the contactor and whichsupply substantially permanent hermetic seals with the glass container,then no provision need be made for precluding exposure of the leading-inwires intcriorly of the container. However. if the leading-in wires -towhich the electrodes 18 and 19 are attached the container. Theelectrodes 18 and 19 may seal so as to preclude their exposure within besecured to the leading-in wires in any suitable manner, such as bywelding or otherwise. The contactor of Figs. 6 and 7 shows the flexibleelectrical conductors connected to the leading-in wires as beingdisposed in a-manner similar to the leading-in conductors shown in Figs.4 and 5. The flexibleconductors connected to the leading-in wires havetheir'ends adjacent to the points of connection embedded in the body ofcement 16. The tip 16' of the container, if desired, may alsobeembedde'd in a body of cement, such as I have hereinbefore described.In this fashion. the envelope is provided with'a double seal at thosepoints where the glass has been scaled during the manufacture of thecontactactor.

The structure shown in Fig. 8 comprises a contactor similar to thatillustrated in Figs. 6 and 7 except that it is of diminutive size. .Theclip holder in this instance comprises two spaced clip portions 20 and21 and the rear of the holder is provided with three openings 22, 23 and24 that'serve as mounting means for the contactor.

I In Fig. 9 we have shown a mercury contactor of simple construction,the envelope of which is completely covered with the cement that we havedescribed in connection with the pinch seal of the contactors shown inthe other figures. The seals are thus provided with a protective coatingas well as the whole of the fragile envelope. The cement coating servesas a shock-absorbing medium and permits the contactor to be more roughlyhandled than has heretofore been possible with contactors not providedwith this external flexible cement covering that serves as ashock-absorbing medium.

While we have herein described several embodiments of our invention, itis to be understood that many modifications may be made therein withoutdeparting from the spirit andscope of the appended claims.

lVe claim:

1. An electric switch comprising an envelope of fragile insulatingmaterial, leadingin wires sealed therethrough and terminating at theirinner ends in electrodes, a body of mercury in said envelope, and acoating of resilient cement applied exteriorly of said envelope toprotect it from mechanical .shocks. i v

2. An electric switch comprising an envelope of fragile insulatingmaterial, leadingin wires sealed therethrough and terminating at theirinner ends in electrodes, a body of mercury in said envelope, and asubstantially impervious and inert coating of resilient and electricalinsulating cement adher- 7 ing to said envelope exteriorly thereof.

' 3. An electric switch comprising 'an enve- ,lope of fragile insulatingmaterial, leading in wires sealed therethrough and terminatdisposedadjacent to each other at one end of said envelope, a body of mercury insaid envelope, an inert gas filling for said envelope, and asubstantially air-tight protective coating of resilient'and inert cementapplied exteriorly of said envelope and super-sealing said envelopewhereat it has been hermetically sealed through the application of heatsaid resilient cement serving to protect said envelope from mechanicalshocks.

4. An electric switch comprising a container of fragile insulatingmaterial, leadingin wires sealed therethrough and terminating attheirinner ends in electrodes, a body of mercury in said container, and anairtight coating of electrical insulating and re silient cementenveloping completely said container, said coating serving as a cushionfor the walls of said container.

5. An electric switch comprisin an envelope of fragile insulatingmateria leadin in wires sealed therethrough at one end of said envelopeand terminating at theirinner ends in electrodes that are positionedadjacent to where said leading-in wires are sealed through saidenvelope, a body of mercuryin said envelope, and an air-tight protectivecoating of resilient and insulating cement applied exteriorly of saidenvelope adj acent to those points whereat said leading-in wires aresealed therein to protect said envelope from mechanical shocks.

6. An electric switch comprising an envelope of fragile insulatingmaterial, leading-in wires sealed therethrough at one end of saidenvelope and terminating at their inner ends in electrodes that arepositioned at one end of said envelope, a body of mercury in saidenvelope, flexible conductors connected to said leading-in wires, and aresilient protective coatiilg of cement applied exteriorly upon saidenvelope adjacent to the points wherea't the said leading-in wires aresealed therein, said cement embedding the points of connection of saidflexible conduc- 1 tors to said leading-in wires and serving to protect"said envelope from mechanical shocks.

7.-' An electric switch comprising an elongated envelop of fragileinsulating material, leading-in wires sealed there-through at one end ofsaid envelope and terminating at their inner ends in electrodes that arepositioned at is connection to said leading-in wires are held firmly inclose contact with the wall of said envelope, said resilient cementserving to protect said envelope from mechanical shocks.

8. An electric switch comprising an elongated envelop of fragileinsulating mateenvelope from mechanical shocks.

9. An electric switch comprising an envelope of lass having leading-inwires sealed therein a jacent to one end of said envelopeand'terminating at their inner ends in electrodes, a body of mercury insaid envelope, the latter being tipped off, and a coating of resilientair-tight cement applied exteriorl of said envelope. and embedding thetippe ofl' portion thereof and the seals through which the leading-inwires are admitted within said envelope.

10. An electric switch comprising a tubular elongated container,leading-in wires sealed in said container through the medium of a pinchseal and spaced from each other transversely of said tubular container,large headed electrodes interiorly of said container connected to saidleading-in wires and spaced from each other longitudinally of thecontainer, and a body of mercury in said container'.

11. An electric switch comprising an elongated glass container, spacedleading-in wires sealed at one end of said container through the mediumof a pinch seal, said leading-in wires being spaced from each othertransversely of the container, electrodes disposed within said containerand connected to said leading-in wires, said electrodes constitutingenlarged heads that are spaced from each other along the longitudinalaxis of said container, a body of mercury housed in said container,flexible conductors connected to .said leading-in wires exteriorly ofsaid container, and a body of insulating cement embedding the exteriorportionsof said lead-- ing-in wires and holding sa' flexible conductorsin close contact wit the exterior surface of said container.

12. An electric switch comprising an elongated glass container, spacedleading-in wires sealed at one end thereof through the medium of a pinchseal whereb said leadingin wires are spaced from eac other transverselyof the container, electrodes disposed within said container andconnected to said leading-in wires, said electrodes constitutm enlargedheads that are spaced from each ot er along the longitudinal axis ofsaid contalner, a ody of mercury housed in said container, flexibleconductors connected to said leading-in wires exteriorly of saidcontainer, a body of electrical insulating and hermetically sealingcement embedding the exterior portions of said leading-in wires andholding said flexible conductors in close contact with the exteriorsurface of said container, and a filling of hydrogen gas within saidcontainer.

13. An electric switch comprising an elongated glass container ofinsulating material, leading-in wires sealed at one end thereof throughthe medium of a pinch seal, enlarged electrodes within said containerand disposed at one end thereof, said electrodes being spaced from eachother along the longitudinal axis of said container which is tippedofi'at its end opposite to said pinch seal, a body of mercury in saidcontainer, flexible conductors connected to said leading-in wiresexteriorly of said container, an insulating cement embedding the pinchseal and the polnts of connection between said flexible conductors andsaid leadin -in Wires, and a second body of cement embe ding thetippedoff portion of said container.

14. An electric switch comprising an elongated tubular container offragile insulating material, leading-in wires sealed at one end thereofthrough the medium of a pinch seal, enlarged headed electrodes on theinner ends of sald leading-in wires and positioned in the end of thecontainer adjacent the pinch seal, flexible conductors connected to theexterior portions of said leading-in wires, a 105 body of mercury insaid container and a body of insulating and resilient cement embeddlngthe pinch seal and the points of connection between said leading-inWires and said flexible conductors whereby said flexible conductors areheld adjacent to the pinch seal, said cement protecting said envelopefrom mechanical shocks.

15. The combination with a holder, of an electric switch disposedtherein and held by 115 said holder about its central portion, saidelectric switch comprising a tubular container, leading-in wires sealedat one end thereof, electrodes disposed in said container and connectedto said leading-in wires, a body of mercury in said container, flexibleconductors connected to said leading-in wires exteriorly of saidcontainer, and a body of insulating and insulating cement embedding theexterior portions of said leading-in wires at the points v 6 maam' nallyof said container and through said holder.

16. An electric switch comprising a tubular elongated container,leading-1n wires 5 sealed in said containerthrough one end thereof andspaced from each other transversely of said container, enlarged headedelectrodes in said container that are connected to said leading-in wiresand spaced from each othera, relatively short distance longitudinally ofthe container, and disposed at one end of said container, and a body ofmercury in said container.

17. An electricswitch comprising a tubular elongated container,leading-in wires sealed therein and spaced from each other transverselyof said container, enlarged headed electrodes housed in said containerand at one end thereof that are severally connected to said leading-inwires and spaced a relatively short distance from eachotherlongitudinal- 131 of the container,'and a body of mercury in saidcontainer. e

. 18. An electric switch comprising an hermetically sealed container offragile insulating material, a leading-in wire sealed therethrough andterminatmg at its inner end in an electrode, a body of mercury in saidcontainer and an air-tight coating of cement applid exteriorly to saidcontainer and covering at least that portion thereof whereat saidleading-in wire is sealed through said container, said cement providingan additional hermetic seal around said leading-in wire seal andprotecting said container thereat from mechanical shocks.

In witness whereof, we have hereunto subscribed our names. 40 p LOUIS A.M. PHELAN.

7 PAUL S. BEAR.

